Data processing systems require information transfer between data processing system components. There are several methods to provide information transfer within data processing systems. One method that is very advantageous is to simultaneously transfer information between several data processing system elements by using a cross point switch. An example of a cross point switch is illustrated in U.S. Pat. No. 4,630,045, entitled "Controller for a cross Point Switching Matrix". A cross point switch provides simultaneous communication connections between pairs of data processing system elements so that several of these connected pairs may exchange information at the same time through the switch. The cross point switch in U.S. Pat. No. 4,630,045 illustrates the prior art implementation of a cross point switch, whereby the ports of the cross point switch that are connected to the data processing elements are interconnected to a switching matrix and a centralized control circuit which governs the operations of the ports and their interconnection through the switch matrix itself.
U.S. Pat. No. 4,814,762, entitled "Delta Network Control of a Cross Point Switch", illustrates another embodiment of a cross point switch where the actual communications between the ports of a cross point switch are contained in a delta network. According to the teachings of this patent, when a port is attempting to access another port it sends a request message for the specified connection over the delta network. This communication takes place outside of the cross point switch itself. The present invention is intended to provide communications through the cross point switch and, thus, provides inband communication for not only the data transfer but also for specifying the interconnections desired.
U.S. Pat. No. 4,752,777, entitled "Delta Network of a Cross Point Switch", is a continuation of the parent application for U.S. Pat. No. 4,814,762 and teaches the delta network for control of cross point switch ports.
U.S. Pat. No. 4,695,999, entitled "Cross Point Switch of Multiple Autonomous Planes", discloses a multiplaned cross point switch. However, the control of ports connected to the cross point switch is disclosed by this patent.
U.S. Pat. No. 4,845,722, entitled "Computer Interconnect Coupler Employing Cross Bar Switching", discloses an interconnect coupler system that includes a centralized switch logic circuit for controlling the switch matrix.
U.S. Pat. No. 4,580,011, entitled "Distributed Processing Telephone Switching System", discloses a switching system having a centralized controller that receives control signals from the line couplers to direct interconnection through a cross point switching matrix.
IBM Technical Disclosure Bulletin, Vol. 28, No. 2, Jul., 1985, pp. 510-512, entitled "Fast Set-Up Time Circuit Switch With Distributed Control", discloses a switch matrix control system having ports that communicate with a central management controller to control the operation of a cross point switch.
IBM Technical Disclosure Bulletin, Vol. 29, No. 3, Aug., 1986, pp. 1356-1360, entitled "Dynamically Reconfigurable Integrated Switch", discloses a reconfigurable switch designed to support multiple networks of different types. This configuration includes a switch controller that controls the access of the ports to the switch.
IBM Technical Disclosure Bulletin, Vol. 32, No. 1, Jun., 1989, pp. 427-433, entitled "Control Mechanism for a Packet Bus Communication Controller", discloses a controller for a packet bus. A packet bus allows only a single transfer of information at a time, as opposed to a cross point switch which allows simultaneous and continuous transfers of information between communicating pairs of system elements.
IBM Technical Disclosure Bulletin, Vol. 20, No. 2, Jul., 1977, pp. 816-817, entitled "Cross Point Switch for ATS", discloses a cross point switch with a controller which regulates port access over a cross point switch.
IBM Technical Disclosure Bulletin, Vol. 29, No. 4, Sep., 1986, pp. 1769-1771, entitled "Race Resolution in TDM Any-To-Any Path Connections in a Space Division Switch", discloses a switch providing "packet-like" communication capability. As discussed previously, packet transmission provides for only a single pair of communications at a time.
IBM Technical Disclosure Bulletin, Vol. 2.7, No. 4B, Sep., 1984, pp. 2704-2708, entitled "Variable Configuration Hybrid Space and Packet Switching Network", discloses a three level switching mechanism for a packet transmission network using central control to establish a path interconnection.
IBM Technical Disclosure Bulletin, Vol. 24, No. 7A, Dec., 1981, pp. 3352-3356, entitled "Multipath Channel-To-Channel Adapter Cross-Point Switch", discloses a centralized control switching mechanism allowing interprocessor communication through input/output channels.
IBM Technical Disclosure Bulletin, Vol. 28, No. 8, Jan., 1986, pp. 3272-3273, entitled "Parallel Processor Architecture to Control Multiple Independent Telecommunication Switching Nodes", describes a telecommunication system using distributed parallel processors to control a distribution network.
As previously discussed, other methods of data transfer are provided in the prior art. One such method employs an information bus allowing only one message passing at a time. An example of this bus method is illustrated in U.S. Pat. No. 4,586,175, entitled "Method for Operating a Packet Bus for Transmission of Asynchronous and Pseudosynchronous Signals". This patent discloses a bus controlled by two bus controllers. U.S. Pat. No. 4,363,093, entitled "Processor Intercommunications System", discloses a local area network intercommunications system between processors. Again, only one message will be allowed on the system at a time. U.S. Pat. No. 4,821,170, entitled "Input/Output System for Multiprocessors", also discloses a system providing two system buses, but not employing a switch to facilitate intersystem communication.
Other examples of bus type communication are illustrated in U.S. Pat. No. 4,704,606, entitled "Variable Length Packet Switching System". This patent discloses a packet switching system for variable length packets. U.S. Pat. No. 4,631,534, entitled "Distributed Packet Switching System", discloses a packet switching system where each port includes the intelligence to provide destination port and station addresses in the packets. U.S. Pat. No. 4,630,258, entitled "Packet Switched Multiport Memory N.times.M Switch Node and Processing Method", discloses a packet switching system using an N.times.M switch from N input ports to be routed to M output ports. The switch is centrally controlled.
U.S. Pat. No. 4,773,069, entitled "Robust Routed Tree Network", discloses a data transmission network including modems, and having at least two controllers interconnected to the modems.
Other general communication teachings illustrating a switch include IBM Technical Disclosure Bulletin, Vol. 25, No. 7A, Dec., 1982, pp. 3578-3582, entitled "Data Base Control and Processing System", discloses a host processor communicating with a plurality of satellite processors through a data switch matrix. The switch and the operation of the satellites are being controlled by the host processor. IBM Technical Disclosure Bulletin, Vol. 29, No. 7, Dec., 1986, pp. 3070-3072, entitled "Rotary Switch", discloses a rotary switch. IBM Technical Disclosure Bulletin, Vol. 30, No. 1, Jun., 1987, pp. 403-405, entitled "Dynamic Time Slot Assignment Architecture for a Digital Telephone Switch", discloses a single port providing access to a digital telephone switch system. IBM Technical Disclosure Bulletin, Vol. 11, No. 10, Mar., 1969, pp. 1231-1232, entitled "Interconnection Control Networks", discloses a multiply redundant switching arrangement for a digital computer.
All of the prior art previously discussed discloses the use of centralized control for the switching network. It is an object of the present invention to provide a distributed control across the ports connected to the switch to more cost effectively regulate the interconnection of the ports to the switch, and, thus, communication across the switch.